A new study published in the online edition of Current Biology, a scientific journal, on April 22 found that napping and dreaming immediately following study sessions improves spatial memory performance.

Researchers from Harvard University trained participants "on a virtual navigation task and then retested on the same task 5 hr after initial training. Improved performance at retest was strongly associated with task-related dream imagery during an intervening afternoon nap. Task-related thoughts during wakefulness, in contrast, did not predict improved performance."

Robert Stickgold, co-author of the study at Harvard, explained, "we think that the dreams are a marker that the brain is working on the same problem at many levels. The dreams might reflect the brain's attempt to find associations for the memories that could make them more useful in the future."

"Some have viewed dreaming as entertainment, but this study suggests it is a by-product of memory processing," he said. Ironically, even if you don't remember all of your dreams, the researchers believe that may not be a factor as many do not recall the majority of their dreams.

The researchers intend to replicate the study with a "full night of sleep as opposed to a nap."

Full study, "Dreaming of a Learning Task Is Associated with Enhanced Sleep-Dependent Memory Consolidation": http://www.cell.com/current-biology/abstract/S0960-9822%2810%2900352-0